Effect of the angiotensin-receptor-neprilysin inhibitor LCZ696 compared with enalapril on mode of death in heart failure patients

Neprilysin inhibition in heart failure: mechanisms and substrates beyond modulating natriuretic peptides

The autonomic nervous system, the renin-angiotensin-aldosterone system, and the natriuretic peptide system represent critical regulatory pathways in heart failure and as such have been the major targets of pharmacological development. The introduction and approval of angiotensin receptor neprilysin inhibitors (ARNi) have broadened the available drug treatments of patients with chronic heart failure with reduced ejection fraction. Neprilysin catalyses the degradation of a number of vasodilator peptides, including the natriuretic peptides, bradykinin, substance P, and adrenomedullin, as well as vasoconstrictor peptides, including endothelin-1 and angiotensin I and II. We review the multiple, potentially competing, substrates for neprilysin inhibition, and the resultant composite clinical effects of ARNi therapy. A mechanistic understanding of this novel therapeutic class may provide important insights into the expected on-target and off-target effects when this agent is more widely prescribed.

Limitations of Sacubitril/Valsartan in the Management of Heart Failure

BACKGROUND

The PARADIGM-HF (Prospective comparison of ARNI with ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure) trial was a double-blind trial that randomized 8442 patients with heart failure (HF) with reduced ejection fraction (HFrEF) to receive twice daily dosing of either 200 mg of LCZ696 or 10 mg of enalapril in addition to standard medical therapy for HF.

AREAS OF UNCERTAINTY

Limitations of this trial include (1) sacubitril has not been tested by itself in the treatment of HFrEF; (2) the maximum recommended dose of valsartan for the treatment of HFrEF was used in this trial, but the maximum recommended dose of enalapril for the treatment of HFrEF was not used; (3) a run-in phase was used in this trial to test the tolerability of LCZ696, and patients who had adverse effects in this period were excluded from randomization; (4) the percent of blacks enrolled in this trial was only 5%; (5) LCZ696 caused a 14% incidence of hypotension; (6) neprilysin inhibition might favor the development of Alzheimer dementia, which was not assessed in the PARADIGM-HF trial; (7) patients with severe symptomatic HF were underrepresented in this trial; (8) major exclusions from this trial included an acute coronary event in the last 3 months, severe pulmonary disease, hepatic impairment, and an estimated glomerular filtration rate <30 mL per minute per 1.73 m.

DATA SOURCES

Review of the PARADIGM-HF trial.

RESULTS

At 27-month follow-up, the PARADIGM-HF trial showed that compared with enalapril, LCZ696 reduced the composite of cardiovascular death or hospitalization for HF 20% (absolute risk reduction 4.7%, P < 0.001).

CONCLUSIONS

The numerous limitations discussed under the areas of uncertainty should be considered when prescribing LCZ696 for the treatment of HFrEF.

Focus on the Novel Cardiovascular Drug LZC696: from Evidence to Clinical Consideration

LCZ696, a first-in-class angiotensin receptor neprilysin inhibitor (ARNI), is comprised of the angiotensin receptor blocker valsartan and the neprilysin inhibitor pro-drug sacubitril (AHU377). After oral administration, AHU377 is rapidly metabolized to the active neprilysin inhibitor LBQ657. LCZ696 exerts its effects of diuresis, natriuresis, vasodilation and aldosterone secretion inhibition through simultaneous renin-angiotensin-aldosterone system (RAAS) blockade and natriuretic peptides system (NPS) enhancement. Powerful evidence including PARAMETER and PRARDIGM-HF trials have shown that LCZ696 outperforms RAAS inhibition in treating patients with hypertension and heart failure with reduced ejection fraction (HFrEF), and is well tolerated. In addition, accumulating evidence also suggests its potential use in heart failure with preserved ejection fraction (HFpEF), chronic kidney disease (CKD), post-myocardium infarction (post-MI) and stroke. Both the FDA and CHMP have approved LCZ696 for treatment of HFrEF. Despite all this, some special issues (e.g. use in specific subgroups, adverse events, contraindications and cost-effectiveness analysis) should be considered before its implementation in clinical practice.

Angiotensin receptor neprilysin inhibitor LCZ696: pharmacology, pharmacokinetics and clinical development

Heart failure still has a significant disease burden with poor outcomes worldwide despite advances in therapy. The standard therapies have been focused on blockade of renin–angiotensin–aldosterone system with angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and mineralocorticoid antagonists and the sympathetic nervous system with β-blockers. The natriuretic peptide system is a potential counter-regulatory system that promotes vasodilatation and natriuresis. Angiotensin receptor neprilysin inhibitors are a new class drug capable of blocking the renin–angiotensin–aldosterone system and enhancing the natriuretic peptide system to improve neurohormonal balance. The success of the PARADIGM-HF trial with LCZ696 and its approval for heart failure treatment is likely to generate a paradigm shift. This review summarises the current knowledge of LCZ696 with a focus on pharmacology, pharmacokinetics and pharmacodynamics, mechanisms of action, clinical efficacy and safety.

Sacubitril/Valsartan (LCZ696) in Heart Failure

It has been known since the 1990s that long-term morbidity and mortality is improved in patients with heart failure with reduced ejection fraction (HFrEF) by treatments that target the renin-angiotensin-aldosterone system (RAAS). It has also long been thought that enhancement of the activity of natriuretic peptides (NPs) could potentially benefit patients with HFrEF, but multiple attempts to realize this benefit had failed over the years - until 2014, when a large, phase III, randomized, controlled clinical trial (PARADIGM-HF) was completed comparing sacubitril/valsartan with enalapril, a well-established treatment for HFrEF. Sacubitril/valsartan (formerly known as LCZ696) is a first-in-class angiotensin receptor neprilysin inhibitor (ARNI) that simultaneously suppresses RAAS activation through blockade of angiotensin II type 1 receptors and enhances vasoactive peptides including NPs through inhibition of neprilysin, the enzyme responsible for their degradation. In PARADIGM-HF, patients with HFrEF treated with sacubitril/valsartan had 20% less risk for cardiovascular death or hospitalization for heart failure (the primary endpoint), 20% less risk for cardiovascular death, 21% less risk for first hospitalization for heart failure, and 16% less risk for death from any cause, compared with enalapril (all p < 0.001). Concerning tolerability, the sacubitril/valsartan group had higher proportions of patients with hypotension and nonserious angioedema but lower proportions with renal impairment, hyperkalemia, and cough, compared with the enalapril group. The use of sacubitril/valsartan has been endorsed by the latest heart failure treatment guidelines in Europe and the USA. This chapter reviews the discoveries, scientific reasoning, and clinical evidence that led to the development of sacubitril/valsartan, the first novel therapy in a new drug class to improve survival in HFrEF in the last 15 years.

Angiotensin Receptor-Neprilysin Inhibition

The novel combination sacubitril/valsartan represents a new therapeutic approach in the management of heart failure. With the simultaneous blockage of the enzyme neprilysin (by sacubitril) and angiotensin II receptors (by valsartan), this combination reduces the degradation of natriuretic peptides and other counterregulatory peptide systems while avoiding the deleterious effect of angiotensin II receptors activation and thereby encompasses a beneficial impact of 2 important neurohormonal pathways activated in heart failure. As opposed to previously tested neprilysin inhibitors, sacubitril/valsartan represents a more effective method in reducing morbidity and mortality in heart failure, while preserving a safety profile comparable to well-established, standard, angiotensin-converting enzyme inhibitor's therapy.

Treatment of Heart Failure With Reduced Ejection Fraction-Recent Developments

Heart failure with reduced ejection fraction (HFrEF) represents at least half of the cases of heart failure, which is a syndrome defined as the inability of the heart to supply the body's tissues with an adequate amount of blood under conditions of normal cardiac filling pressure. HFrEF is responsible for high costs and rates of mortality, morbidity, and hospital admissions, mainly in developed countries. Thus, the need for better diagnostic methods and therapeutic approaches and consequently better outcomes is clear. In this article, we review the principal aspects of pathophysiology and diagnosis of HFrEF, with focus on emerging biomarkers and on recent echocardiographic methods for the assessment of left ventricular function. Furthermore, we discuss several major developments in pharmacological and nonpharmacological treatment of HFrEF in the last years, including cardiac resynchronization therapy, implantable cardioverter defibrillators, and the recent and promising drug LCZ696, focusing on current indications, unanswered questions, and other relevant aspects.

Sacubitril/Valsartan: A Review in Chronic Heart Failure with Reduced Ejection Fraction

Sacubitril/valsartan (Entresto™; LCZ696) is an orally administered supramolecular sodium salt complex of the neprilysin inhibitor prodrug sacubitril and the angiotensin receptor blocker (ARB) valsartan, which was recently approved in the US and the EU for the treatment of chronic heart failure (NYHA class II-IV) with reduced ejection fraction (HFrEF). In the large, randomized, double-blind, PARADIGM-HF trial, sacubitril/valsartan reduced the incidence of death from cardiovascular causes or first hospitalization for worsening heart failure (composite primary endpoint) significantly more than the angiotensin converting enzyme (ACE) inhibitor enalapril. Sacubitril/valsartan was also superior to enalapril in reducing death from any cause and in limiting the progression of heart failure. Sacubitril/valsartan was generally well tolerated, with no increase in life-threatening adverse events. Symptomatic hypotension was significantly more common with sacubitril/valsartan than with enalapril; the incidence of angio-oedema was low. Therefore, sacubitril/valsartan is a more effective replacement for an ACE inhibitor or an ARB in the treatment of HFrEF, and is likely to influence the basic approach to treatment.

Sacubitril/valsartan in heart failure: latest evidence and place in therapy

Despite significant therapeutic advances, patients with chronic heart failure (HF) remain at high risk for HF progression and death. Sacubitril/valsartan (previously known as LCZ696) is a first-in-class medicine that contains a neprilysin (NEP) inhibitor (sacubitril) and an angiotensin II (Ang-II) receptor blocker (valsartan). NEP is an endopeptidase that metabolizes different vasoactive peptides including natriuretic peptides, bradykinin and Ang-II. In consequence, its inhibition increases mainly the levels of both, natriuretic peptides (promoting diuresis, natriuresis and vasodilatation) and Ang-II whose effects are blocked by the angiotensin receptor blocker, valsartan (reducing vasoconstriction and aldosterone release). Results from the 8442 patient PARADIGM-HF study showed in patients with New York Heart Association (NYHA) class II-IV and reduced ejection fraction treated with LCZ696 (versus enalapril), the following benefits: reduction of the risk of death from cardiovascular causes by 20%; reduction of HF hospitalizations by 21%; reduction of the risk of all-cause mortality by 16%. Overall there was a 20% risk reduction on the primary endpoint, composite measure of cardiovascular (CV) death or time to first HF hospitalization. PARADIGM-HF was stopped early after a median follow up of 27 months. Post hoc analyses of PARADIGM-HF as well as the place in therapy of sacubitril/valsartan, including future directions, are included in the present review.

Changing the treatment of heart failure with reduced ejection fraction: clinical use of sacubitril-valsartan combination

Despite significant therapeutic advances, patients with chronic heart failure (HF) remain at high risk of morbidity and mortality. Sacubitril valsartan (previously known as LCZ696) is a new oral agent approved for the treatment of symptomatic chronic heart failure in adults with reduced ejection fraction. It is described as the first in class angiotensin receptor neprilysin inhibitor (ARNI) since it incorporates the neprilysin inhibitor, sacubitril and the angiotensin II receptor antagonist, valsartan. Neprilysin is an endopeptidase that breaks down several vasoactive peptides including natriuretic peptides (NPs), bradykinin, endothelin and angiotensin II (Ang-II). Therefore, a natural consequence of its inhibition is an increase of plasmatic levels of both, NPs and Ang-II (with opposite biological actions). So, a combined inhibition of these both systems (Sacubitril / valsartan) may enhance the benefits of NPs effects in HF (natriuresis, diuresis, etc) while Ang-II receptor is inhibited (reducing vasoconstriction and aldosterone release). In a large clinical trial (PARADIGM-HF with 8442 patients), this new agent was found to significantly reduce cardiovascular and all cause mortality as well as hospitalizations due to HF (compared to enalapril). This manuscript reviews clinical evidence for sacubitril valsartan, dosing and cautions, future directions and its considered place in the therapy of HF with reduced ejection fraction.

Heart Failure Therapy in 2016

Heart failure (HF) continues to afflict millions of Americans, resulting in substantial clinical and economic burden to our society. Recent literature has highlighted the role of 2 novel therapies (an angiotensin receptor blocker/neprilysin inhibitor and ivabradine) in further reducing residual disease in HF. Simultaneously, evidence has mounted suggesting that older therapies like digoxin are not effective in contemporary practice and, in fact, may be harmful. This editorial summarizes the most recently published articles pertaining to both new and old HF therapies and provides a call to action to pharmacists on how to shift patients toward effective drug regimens.

Sacubitril/Valsartan: A Novel Cardiovascular Combination Agent

Sacubitril/valsartan [LCZ696 (Entresto), Novartis Pharmaceuticals Corp.] is the first in a new class of drugs that combines neprilysin inhibition with angiotensin II receptor antagonism, the combination of which acts to increase endogenous natriuretic peptides while inhibiting the renin-angiotensin-aldosterone system. Sacubitril/valsartan has been studied in the treatment of hypertension, heart failure with reduced ejection fraction (HFrEF), and heart failure with preserved ejection fraction (HFpEF) and has demonstrated clinical efficacy in blood pressure reduction in hypertensive patients with and without HFpEF and a reduction in hospitalizations and mortality for patients with HFrEF. Research to evaluate clinical outcomes in HFpEF is ongoing. Sacubitril/valsartan is approved to reduce hospitalization and risk of cardiovascular death for patients with HFrEF in New York Heart Association (NYHA) functional class II-IV. The product is as well tolerated as an angiotensin-converting enzyme inhibitor, with the most common side effect being hypotension. Expectedly, it is much more costly than generic angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists, which will be a factor in determining how widespread the use of this agent will be. In summary, although the number of published studies evaluating its use is limited, sacubitril/valsartan represents a promising new treatment option for patients with HFrEF. Ongoing studies will continue to refine the role of this agent in clinical practice.

[New therapeutic era in heart failure with reduced ejection fraction: Which population of French patients is concerned?]

A new class of cardiovascular drugs, angiotensin receptor neprilysin inhibitors, has shown its efficacy in the PARADIGM-HF study in replacement of renin-angiotensin blockers in symptomatic heart failure patients with reduced ejection fraction, and already treated according to the recommendations. Recent French epidemiological data in the literature allow assessing the number of French patients who could be concerned by the new treatment in taking account the different parameters from the PARADIGM-HF study.

Kicking the tyres of a heart failure trial: physician response to the approval of sacubitril/valsartan in the USA

Angiotensin receptor-neprilysin inhibition has been shown to be superior to target doses of an ACE inhibitor in reducing the risk of cardiovascular death and clinical disease progression in patients with chronic heart failure and a reduced EF. Nevertheless, although sacubitril/valsartan has been available in the USA for a year, uptake of the drug by practitioners has been slow, in part because of misconceptions about the pivotal trial that demonstrated its efficacy in heart failure (PARADIGM-HF). This review addresses questions that have been raised in the USA about the design of the trial as well as the patients who were studied, the replicability and applicability of the results, and the safety of neprilysin inhibition. The totality of evidence indicates that the PARADIGM-HF trial used an appropriate comparator; enrolled patients typical of those seen in the community with mild to moderate symptoms; yielded highly persuasive and replicable results; and demonstrated benefits that are applicable to patients taking subtarget doses of ACE inhibitors and ARBs. Regulatory review in the USA concluded that the established advantages of sacubitril/valsartan on cardiovascular death and disease progression outweighed hypothetical uncertainties about the long-term effects of neprilysin inhibition in patients who might not have survived without the drug. Accordingly, both the new US and European Society of Cardiology heart failure guidelines recommend sacubitril/valsartan as the preferred approach to inhibiting the renin-angiotensin system in patients with chronic heart failure who are currently receiving an ACE inhibitor or ARB.

Discovery of novel small molecule inhibitors of cardiac hypertrophy using high throughput, high content imaging

Chronic cardiac hypertrophy is maladaptive and contributes to the pathogenesis of heart failure. The objective of this study was to identify small molecule inhibitors of pathological cardiomyocyte hypertrophy. High content screening was performed with primary neonatal rat ventricular myocytes (NRVMs) cultured on 96-well plates and treated with a library of 3241 distinct small molecules. Non-toxic hit compounds that blocked hypertrophy in response to phenylephrine (PE) and phorbol myristate acetate (PMA) were identified based on their ability to reduce cell size and inhibit expression of atrial natriuretic factor (ANF), which is a biomarker of pathological cardiac hypertrophy. Many of the hit compounds are existing drugs that have not previously been evaluated for benefit in the setting of cardiovascular disease. One such compound, the anti-malarial drug artesunate, blocked left ventricular hypertrophy (LVH) and improved cardiac function in adult mice subjected to transverse aortic constriction (TAC). These findings demonstrate that phenotypic screening with primary cardiomyocytes can be used to discover anti-hypertrophic lead compounds for heart failure drug discovery. Using annotated libraries of compounds with known selectivity profiles, this screening methodology also facilitates chemical biological dissection of signaling networks that control pathological growth of the heart.

New Management Strategies in Heart Failure

Despite >100 clinical trials, only 2 new drugs had been approved by the US Food and Drug Administration for the treatment of chronic heart failure in more than a decade: the aldosterone antagonist eplerenone in 2003 and a fixed dose combination of hydralazine-isosorbide dinitrate in 2005. In contrast, 2015 has witnessed the Food and Drug Administration approval of 2 new drugs, both for the treatment of chronic heart failure with reduced ejection fraction: ivabradine and another combination drug, sacubitril/valsartan or LCZ696. Seemingly overnight, a range of therapeutic possibilities, evoking new physiological mechanisms, promise great hope for a disease that often carries a prognosis worse than many forms of cancer. Importantly, the newly available therapies represent a culmination of basic and translational research that actually spans many decades. This review will summarize newer drugs currently being used in the treatment of heart failure, as well as newer strategies increasingly explored for their utility during the stages of the heart failure syndrome.

Localization of corin and atrial natriuretic peptide expression in human renal segments

Atrial natriuretic peptide (ANP)-mediated natriuretic response is a well-established cardiac endocrine function. Corin is a transmembrane protease that activates ANP in the heart. Corin expression has been detected in non-cardiac tissues including the kidney. Here we examined corin, pro-ANP/ANP and natriuretic peptide receptor-A (NPR-A) expression in human renal segments. By immunostaining and in situ hybridization, we found similar corin, pro-ANP/ANP and NPR-A protein and mRNA expression in human renal segments. The expression was most abundant in the proximal convoluted tubules and the medullary connecting ducts. In the proximal tubules, corin protein was present in the apical membrane region underneath the brush border where the ANP-degrading protease neprilysin was abundant. These results suggest that corin-mediated pro-ANP activation may occur in renal segments and that locally produced ANP may act in an autocrine manner to regulate sodium and water reabsorption in situ Our results also point to the proximal convoluted tubules as a major site for local ANP action. Such a renal corin/ANP autocrine mechanism may differ from the cardiac corin/ANP endocrine mechanism in regulating sodium homoeostasis under physiological and pathological conditions.

The neprilysin pathway in heart failure: a review and guide on the use of sacubitril/valsartan

Inhibition of neurohumoural pathways such as the renin angiotensin aldosterone and sympathetic nervous systems is central to the understanding and treatment of heart failure (HF). Conversely, until recently, potentially beneficial augmentation of neurohumoural systems such as the natriuretic peptides has had limited therapeutic success. Administration of synthetic natriuretic peptides has not improved outcomes in acute HF but modulation of the natriuretic system through inhibition of the enzyme that degrades natriuretic (and other vasoactive) peptides, neprilysin, has proven to be successful. After initial failures with neprilysin inhibition alone or dual neprilysin-angiotensin converting enzyme (ACE) inhibition, the Prospective comparison of angiotensin receptor neprilysin inhibitor (ARNI) with ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure trial (PARADIGM-HF) trial demonstrated that morbidity and mortality can be improved with the angiotensin receptor blocker neprilysin inhibitor sacubitril/valsartan (formerly LCZ696). In comparison to the ACE inhibitor enalapril, sacubitril/valsartan reduced the occurrence of the primary end point (cardiovascular death or hospitalisation for HF) by 20% with a 16% reduction in all-cause mortality. These findings suggest that sacubitril/valsartan should replace an ACE inhibitor or angiotensin receptor blocker as the foundation of treatment of symptomatic patients (NYHA II–IV) with HF and a reduced ejection fraction. This review will explore the background to neprilysin inhibition in HF, the results of the PARADIGM-HF trial and offer guidance on how to use sacubitril/valsartan in clinical practice.

Therapeutic options of Angiotensin Receptor Neprilysin inhibitors (ARNis) in chronic heart failure with reduced ejection fraction: Beyond RAAS and sympathetic nervous system inhibition

In heart failure, in addition to the renin-angiotensin-aldosterone system and sympathetic nervous system, the natriuretic peptide (NP) system plays a fundamental role among compensating mechanisms. The NPs undergo rapid enzymatic degradation that limits their vasorelaxant, natriuretic, and diuretic actions. Degradation of NPs is partially due to the action of neprilysin, which is a membrane-bound endopeptidase found in many tissues. This article summarizes recent findings on a new natriuretic peptide-enhancing drug and their implication for future pharmacological treatment of patients suffering from heart failure with reduced ejection fraction.

Should Angiotensin Receptor Neprilysin Inhibitors Replace Angiotensin-converting Enzyme Inhibitors in Heart Failure With a Reduced Ejection Fraction?

Angiotensin-converting enzyme inhibitors (ACEIs) have been the cornerstone of treatment of heart failure with reduced ejection fraction (HFrEF) for over two decades. Inhibition of neprilyisin augments vasoactive substances including natriuretic peptides, which may have multiple advantageous effects in chronic HF. Early studies of neprilyisin inhibition led to drug discontinuation due to lack of efficacy or safety concerns. Sacubitril/valsartan is a first-in-class combined angiotensin receptor/neprilysin inhibitor (ARNI). The PARADIGM-HF study demonstrated robust superiority of ARNI compared with enalapril in patients with chronic symptomatic HFrEF, raising the question of whether ACEI should still have a role in the management of HFrEF.

The Mechanism of Action of LCZ696

Heart failure (HF) represents a growing financial burden on healthcare systems and despite therapeutic advances, mortality remains high. Current treatments focus on blocking neurohormonal pathways, such as the renin-angiotensin aldosterone system (RAAS). Recent research has focused on the natriuretic peptide system, which confers beneficial effects in HF, whereas activation of the RAAS and of the sympathetic nervous system has detrimental effects. LCZ696 (sacubutril/valsartan), a first-in-class angiotensin II AT[1] receptor neprilysin inhibitor, has a unique mode of action that targets both pathways. Clinical studies to date indicate that LCZ696 is effective and safe in mild to moderate arterial hypertension and in HF patients with preserved ejection fraction, and has been shown to be superior to enalapril in patients with moderate to severe HF due to reduced left ventricular ejection fraction.

Combining angiotensin II receptor 1 antagonism and neprilysin inhibition for the treatment of heart failure

Sacubitril/valsartan is a novel, first-in-class drug, which combines a neprilysin inhibitor with an angiotensin receptor blocker. Sacubitril inhibits neprilysin endopeptidase, blocking the catabolism of natriuretic peptides (NP), thereby increasing their bioavailability. Valsartan counterbalances the increase of angiotensin II that results from neprilysin inhibition, exerting also the beneficial effects of angiotensin receptor blockers seen in previous HF trials. PARADIGM-HF trial has proved the superiority of sacubitril/valsartan (LCZ696) over ACE inhibitor enalapril to reduce mortality and morbidity of symptomatic HF patients with reduced ejection fraction (HFrEF), setting the grounds for the replacement of ACE inhibitors by sacubitril/valsartan in the management of HFrEF. Sacubitril/valsartan is currently being tested in a phase III trial (PARAGON-HF) in patients with HF with preserved EF. PARAGON-HF is also expected to provide further data regarding the long-term safety of sacubitril/valsartan, hopefully to alleviate concerns regarding the effects of neprilysin inhibition on cognitive function.

A Review of New Pharmacologic Treatments for Patients With Chronic Heart Failure With Reduced Ejection Fraction

Heart failure (HF) impacts an estimated 5.7 million Americans, and its prevalence is projected to increase to more than 8 million Americans in the next 15 years. Key clinical trials have established an evidence-based foundation for treatment of heart failure with reduced ejection fraction (HFrEF). Ivabradine and sacubitril/valsartan, which inhibit the f-channel and the angiotensin receptor and neprilysin, respectively, were recently approved by the Food and Drug Administration for HFrEF. In systolic heart failure, treatment with the If inhibitor ivabradine significantly reduced the combined endpoint of cardiovascular mortality or heart failure hospital admission vs placebo (P < .05). In the Prospective Comparison of angiotensin receptor-neprilysin inhibitor (ARNI) with angiotensin-converting enzyme inhibitor (ACEI) to Determine Impact on Global Mortality and Morbidity in Heart Failure trial, sacubitril/valsartan significantly reduced the combined endpoint of cardiovascular death or heart failure hospitalization vs enalapril (P < .001). The place of therapy with ivabradine and sacubitril/valsartan is defined by these trials and their interplay with guideline-directed medical therapy. Ivabradine and sacubitril/valsartan increase pharmacotherapy options for the treatment of HFrEF but are not yet first-line agents. Clinical application will be better defined in the coming years as practitioners increase their familiarity with ivabradine and sacubitril/valsartan.

Sacubitril/Valsartan

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, call The Formulary at 800-322-4349. The December 2015 monograph topics are rolapitant, insulin degludec, flibanserin, coagulation factor IX (recombinant), and grazoprevir/elbasvir. The Safety MUE is on rolapitant.

Counteracting Protein Kinase Activity in the Heart: The Multiple Roles of Protein Phosphatases

Decades of cardiovascular research have shown that variable and flexible levels of protein phosphorylation are necessary to maintain cardiac function. A delicate balance between phosphorylated and dephosphorylated states of proteins is guaranteed by a complex interplay of protein kinases (PKs) and phosphatases. Serine/threonine phosphatases, in particular members of the protein phosphatase (PP) family govern dephosphorylation of the majority of these cardiac proteins. Recent findings have however shown that PPs do not only dephosphorylate previously phosphorylated proteins as a passive control mechanism but are capable to actively control PK activity via different direct and indirect signaling pathways. These control mechanisms can take place on (epi-)genetic, (post-)transcriptional, and (post-)translational levels. In addition PPs themselves are targets of a plethora of proteinaceous interaction partner regulating their endogenous activity, thus adding another level of complexity and feedback control toward this system. Finally, novel approaches are underway to achieve spatiotemporal pharmacologic control of PPs which in turn can be used to fine-tune misleaded PK activity in heart disease. Taken together, this review comprehensively summarizes the major aspects of PP-mediated PK regulation and discusses the subsequent consequences of deregulated PP activity for cardiovascular diseases in depth.

The Evolution of the Stem Cell Theory for Heart Failure

Various stem cell-based approaches for cardiac repair have achieved encouraging results in animal experiments, often leading to their rapid proceeding to clinical testing. However, freewheeling evolutionary developments of the stem cell theory might lead to dystopian scenarios where heterogeneous sources of therapeutic cells could promote mixed clinical outcomes in un-stratified patient populations. This review focuses on the lessons that should be learnt from the first generation of stem cell-based strategies and emphasizes the absolute requirement to better understand the basic mechanisms of stem cell biology and cardiogenesis. We will also discuss about the unexpected “big bang” in the stem cell theory, “blasting” the therapeutic cells to their unchallenged ability to release paracrine factors such as extracellular membrane vesicles. Paradoxically, the natural evolution of the stem cell theory for cardiac regeneration may end with the development of cell-free strategies with multiple cellular targets including cardiomyocytes but also other infiltrating or resident cardiac cells.

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Varied sources of therapeutic cells and low repair ability of the failing heart contribute to mixed results in clinical trials.

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Consensus is still lacking concerning the appropriate type of therapeutic stem cells.

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A clear understanding of cardiac development and adult cardiogenesis might increase the efficiency of regenerative therapies.

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Delivery of stem cell-derived paracrine factor alone to the damaged heart may be sufficient to activate repair mechanisms.